DESCRIPTION: The investigator proposes to design a small confocal planar array that will be capable of point-by-point scanning of a chip carrying fluorescent probes hybridized to a Si-based substrate. The entire chip would be designed to fit in the CD port of a laptop computer which could be used in clinical labs, offices, and in the field. If successful, the unit would cost about $5,000. For comparison, the Affymetrix scanner will soon be marketed for $80,000.